Features of the geographical position of the Indian Ocean. Indian Ocean: geographical location

The nature of the Indian Ocean has many features in common with the nature of the Pacific Ocean, especially in the organic world of the two oceans.

Geographical position. The Indian Ocean has a peculiar position on the planet: most of it lies in the Southern Hemisphere. In the north, it is bounded by Eurasia and has no connection with the Arctic Ocean.

The shores of the ocean are slightly indented. There are relatively few islands. Large islands are located only on the border of the ocean. There are volcanic and coral islands in the ocean (see map).

From the history of ocean exploration. The shores of the Indian Ocean are one of the areas of ancient civilizations. Some scholars believe that navigation began in the Indian Ocean. Bamboo rafts, which are still used in Indochina, could be the first means of overcoming the expanses of water. In India, catamaran-type ships were created. Images of such ships are carved on the walls of ancient temples. Ancient Indian navigators in those distant times sailed to Madagascar, to East Africa, and possibly to America. The descriptions of sailing routes on the ocean were the first to be compiled by the Arabs. Information about the Indian Ocean began to accumulate from the time of the voyage of Vasco da Gama (1497-1499). At the end of the XVIII century. the first measurements of the depths of this ocean were made by the English navigator J. Cook.

A comprehensive study of the ocean began at the end of the 19th century. The most significant research was carried out by the British expedition on board the Challenger. However, until the middle of the XX century. The Indian Ocean has been poorly studied. Today, dozens of expeditions on research ships from many countries are studying the nature of the ocean, revealing its riches.

Features of the nature of the ocean. The structure of the bottom topography is complex. Mid-ocean ridges divide the ocean floor into three parts (see map). In the western part, a ridge stretches, connecting south of Africa with the Mid-Atlantic Ridge. The center of the ridge is characterized by deep faults, areas of earthquakes and volcanism at the bottom of the ocean. Faults in the earth's crust continue in the Red Sea and come out on land.

The climate of this ocean is formed under the influence of its geographical position. A feature of the climate is the seasonal monsoon winds in the northern part of the ocean, which is located in the subequatorial zone and is significantly influenced by land. Monsoons have a huge impact on weather conditions in the northern part of the ocean.

In the south, the ocean experiences the cooling influence of Antarctica; here lie the most severe regions of the ocean.

The properties of water masses are associated with the characteristics of the climate. The northern part of the ocean warms up well, is deprived of the influx of cold waters and is therefore the warmest. The water temperature here is higher (up to +30°С) than at the same latitudes in other oceans. To the south, the water temperature drops. The salinity of ocean waters on the surface is generally higher than the average salinity of the World Ocean, and in the Red Sea it is especially high (up to 42%).

In the northern part of the ocean, the formation of currents is influenced by the seasonal change of winds. Monsoons change the direction of water movement, cause their vertical mixing, and rebuild the system of currents. In the south, currents are an integral part of the general scheme of currents of the World Ocean (see Fig. 25).

The organic world of the Indian Ocean is similar to the flora and fauna of the Western Pacific. Tropical water masses are rich in plankton, which is especially rich in single-celled algae. Because of them, the surface layer of water becomes very cloudy, changes color. Among the plankton, there are many organisms that glow at night. Various types of fish: sardinella, mackerel, sharks. In the southern part of the ocean - white-blooded fish, such as icefish, etc. Shelf areas and shallow waters near coral reefs are especially rich in life. Thickets of algae form underwater meadows. Giant sea turtles, sea snakes live in the warm waters of the Indian Ocean, there are many cuttlefish and squid from mollusks, and whales and seals near Antarctica.

The Indian Ocean is located in several natural zones (see Fig. 33). In the tropical zone, under the influence of the surrounding land, complexes with different properties of water masses are formed. In the western part of this belt, precipitation is low, evaporation is high, and almost no water comes from land. The water masses here have high salinity. The northeastern part of the belt, on the contrary, receives a lot of precipitation and fresh water from the rivers flowing from the Himalayas. A complex with highly desalinated surface waters is being created here.

Types of economic activity in the ocean. The natural resources of the Indian Ocean as a whole have not yet been sufficiently studied and developed. The ocean shelf is rich in minerals. In the strata of sedimentary rocks at the bottom of the Persian Gulf, deposits of oil and natural gas are huge. Extraction and transportation of oil creates the risk of water pollution. In countries located near the northwestern coasts of the ocean, where there is almost no fresh water, desalination of salt water is being carried out. Fishing is also developed.

Numerous shipping routes pass through the Indian Ocean. There are especially many sea roads in the northern part of the ocean, where small sailing ships are still used. The direction of their movement is associated with the monsoons.

  1. What influence does its physical and geographical position have on the nature of the Indian Ocean?
  2. What is the interaction between the ocean and the surrounding land?
  3. Put the information given in the text on the contour map; make your own symbols.
Scientific - research conference

Topic: "Natural, social and environmental problems of the development of the Indian Ocean."

Target: Deepen and systematize knowledge about the nature of the Indian Ocean; continue to improve practical skills to characterize the climatic conditions of the ocean, the properties of water masses, natural resources, give examples of representatives of the organic world, and establish sources of ocean water pollution; develop communication skills and the ability to work in small groups.

Lesson type: learning new material

During the classes:

  1. Organizing time:
  • greeting students;
  • verification of those present (slide number 1)
  1. Motivation of educational and cognitive activity:

When a person doesn't know

to which pier he is heading,

no wind for him

passing.

(slide number 2)

Seneca

Each person has a place in life where he is happy, where the main dreams come true, a place where the soul constantly strives.

Where so calm and clean. Bottle mail has been delivered to the shores of our state. AT

In 1560, on the coast of England, a poor boatman found a sealed bottle with an unknown message. Since he could not read, he took it to the local judge. As it turned out, this was an extremely important military message.

To prevent the disclosure of military secrets, the Queen of England appointed the special position of the Royal Bottle Opener. Only this official had the right to open the "bottle mail". I appoint Royal Bottle Opener (Secretary).

The letter is wet and part of it is missing, but we will try to read it.

Letter: In December 2004, a catastrophic earthquake occurred, the epicenter of which is in the ... ocean, 250 km from ... the island. Help us figure out why the earthquake started and how long will we endure the calamity?

- Guys, determine on which mainland or island this happened, on the shore of which ocean. The locals also left us the coordinates of that place.

(0 about br, 100 about east)

On what island? And on the shore, what ocean? (slide number 3)

Today, our “creative laboratory” consists of scientists of various specializations: historians, extras, climatologists, zoologists, local people, ecologists, and a secretary.

They gathered at a conference with the aim (slide number 4) to discuss the current state of the nature of the Indian Ocean, the use of its natural resources and the problems arising from intensive economic activity in the ocean.

Guests came to our conference - a representative of the Greenpeace organization, a representative of the school environmental organization Green Sprout

  1. Learning new material:

Conference sections: (slide number 5)

1 section - historians

Section 2 - extras

3 section - climatologists

4th section - zoologists

Section 5 - local residents

Section 6 - ecologists

Section I - historians (2 people)

What is the purpose of research in the Indian Ocean.

(slide number 6)

1 speaker.

The shores of the Indian Ocean are one of the areas of ancient civilizations. The development of the ocean began from the north by Indian, Egyptian and Phoenician navigators, who for 3 thousand years BC.

made voyages in the Arabian and Red Seas, in the Persian Gulf. The first descriptions of sailing routes in the Indian Ocean were made by the Arabs. For European geographical science, information about the ocean began to accumulate from the time of the voyage of Vasco da Gama (1497 - 1499). When Vasco da Gama first sailed through the waters of the Indian Ocean to the shores of India, he did not even imagine its size.

In the northern hemisphere, the ocean is more like a large sea deeply cut into the land. However, for some time the Indian Ocean remained a less explored area of ​​the Earth. At the end of the 18th century the first depth measurements were made here by J. Cook. (Working with the map)

2 speaker.

Compared to other oceans, Indian scientists have paid less attention. Therefore, in 1960, at the initiative of the UN, the International Indian Ocean Expedition began work, which lasted 6 years.

More than 20 countries took part in it. Scientists have completed the study of the mid-ocean ridge of the ocean, thanks to which the existence of a single system of mid-ocean ridges in the World Ocean has been confirmed.

Question: What was the purpose of this expedition?

Answer: The fault zone of the mid-ocean ridge of the Indian Ocean is a "living" section of the earth's crust.

This is evidenced by the presence of hot springs and frequent earthquakes. Sunda Islands - 100 active volcanoes. In December 2004, a catastrophic earthquake occurred, the epicenter of which was located in Indian for 250 km. from the northern edge of Sumatra. People were affected in Indonesia, Sri Lanka, India, Thailand, Malaysia, Burma, Bangladesh and the Maldives.

The disaster also affected some African countries - Seychelles, Somalia, Tanzania, Kenya.

II section - extras (2 people)

What is researched, the main problem: Compare the statistics of the oceans and determine the significance of the Indian Ocean.

(slide number 7)

1 speaker. (slide number 8 - 10)

Scheme No. 1. Dimensions of the Indian Ocean relative to other oceans

Scheme No. 2. Maximum depths of the World Ocean

Scheme number 3. Maximum rainfall

Scheme number 4. Salinity of the oceans
Scheme number 5. The temperature of the waters of the oceans

After analyzing the statistical data, we can conclude that the Indian Ocean and the Pacific have the most signs of similarity.

2 speaker

After analyzing the statistical data, we suggest that you decode the information.

Task number 1: performed on forms.

(slide number 11)

"Digital Dictation"

- After listening to the statement, determine which ocean it is. If we are talking about the Pacific Ocean, write down the number "1", if about the Indian - the number "2".

Pacific Ocean - 1
Indian Ocean - 2

(Assignment clarification)

1) The third largest ocean on Earth.
2) The name of the ocean was given by F.

Magellan.
3) The Mariana Trench is located in this ocean.
4) The northern part of the ocean washes the mainland Eurasia.
5) One of the seas of the ocean has the highest salinity in the world.
6) This ocean is connected to the Arctic Ocean by the Bering Strait.
7) The richest oil field on the shelf of the Persian Gulf.
8) The warmest ocean in terms of surface water temperature.
9) In the west, the ocean washes Eurasia, in the east - America.
10) In the northern part of the ocean - a powerful monsoon current.

Section III - climatologists (3 people)

What is researched, the main problem: Why is the Indian Ocean the warmest.

(slide number 12)

Microphone Method

  1. I think that the peculiarities of the climatic conditions of the Indian Ocean are determined by the position of its greater part in the equatorial and tropical latitudes. The climate is also influenced by the huge landmass (Mainland Eurasia) from the north, as well as the monsoonal circulation. (work at the card)
  2. Therefore, I believe that the monsoon circulation forms monsoonal circulations of currents here (Southern Equatorial Current, Somali, Monsoon). This phenomenon is observed only in this ocean.

    They change direction twice a year.

  3. As a result, the water warms up at the equator to + 27 0С + 320С, in the north + 40 0С (Bay of Bengal).
  4. Zoning is also manifested in the distribution of precipitation: the equator is 2000 - 3000 mm. per year, tropics 100 mm.

    per year (Persian Gulf).

  5. Precipitation affects salinity

Equator - 34%0

tropics - 37%

Red Sea - 40-42% 0

Task number 2: put geographical nomenclature on the contour map.

(slide number 12)

IV section - zoologists (2 people)

What is researched, the main problem: What caused the originality and uniqueness of the animal and plant world. (slide number 13)

1 speaker. (slide number 14)

We explored the fauna of the Indian Ocean and found out that in the first half of the 20th century, a fish was caught near the tropical coast of Africa, which became a real sensation.

We are talking about the prehistoric fish coelacanth (latimeria), which was thought to have become extinct 70 million years ago. However, in 1938, a coelacanth was caught alive in African waters for the first time. Modern coelacanths are among the rarest living creatures that have remained virtually unchanged for 400 million years. They have a special shape of the skull, resembling a brain box. For example, instead of the hard spine characteristic of all vertebrates, coelacanths have a thick-walled elastic tube.

2 speaker. (slide number 15)

The organic world is extremely rich in the northern part of the tropical region of the ocean (the Red and Arabian seas, the Persian and Bengal bays). Numerous fish species are found here - sardinella, various sharks, mackerel, flying fish. Such wealth is associated with the flow of a large amount of nutrients into the ocean along with the river waters of the continents.

In the temperate and polar latitudes of the Indian Ocean, there are many squids, mammals: whales, pinnipeds, dolphins. Among the birds there are albatrosses, frigates, penguins.

Task number 3: complete the task in the form for matching logical pairs. Students submit their answer sheets to the jury. (slide number 16)

Section V - local population (2 people)

What is researched, the main problem: What are the social and economic problems of the local population.

Why is it so attractive to tourists? (slide number 17)

  1. (Indian dance). (slide number 18)

Teacher: Dear scientists, did you, of course, find out which state introduced its culture to us?

Speaker: A corner of the temples, the beaches of Goa and the shooting of Indian films can unfold right before your eyes.

The islands of Bali, the Seychelles, the Red Sea, the Maldives are one of the most popular year-round destinations in world tourism.

This is not surprising: consistently high air and water temperatures all year round and beautiful nature provide an excellent beach holiday, and the excursion program in Indonesia is exotic and varied.

Mostly couples come here for their honeymoon trips.

  1. Report. The Indian Ocean is currently the most dangerous in the world. And not because of sharks, although they are found here in abundance, but because of sea robbers - pirates.

    Modern pirates are not old warriors with an eye patch and a wooden leg. These are criminals on high-speed vessels, armed with the latest technology. They attack yachts, cargo ships and tankers, plunder them, killing crews and passengers.
    The first information about the pirates who began to operate off the coast of Somalia appeared in the 90s of the last century.

    However, then their actions were fragmented and unsystematic. At the beginning of the new century, the activity of Somali pirates intensified. From March 2005 to June 2006 alone, they attacked dozens of merchant ships in the Indian Ocean.

    Even then, the transitional government of Somalia repeatedly appealed to the countries of East Africa with a request for assistance in curbing the pirates.
    May 20, 2007

    The UN called for international action against the "scourge of piracy" off the coast of Somalia.
    Currently, several ship groups and individual ships are resisting the pirates to one degree or another.

In general, the problem of piracy off the coast of Somalia is fraught with at least three consequences for the world community:

Firstly, it has created a real threat to the safety of maritime navigation in this area and has already negatively affected a number of economic processes.

Thus, the pirates disrupted the tuna fishing season, forcing over 50 fishing vessels to leave for nearby ports.

Second, the proceeds of piracy, which come from ransoms from captured ships and their crews, may in part fuel the many armed conflicts in Somalia. In addition, individual captured ships themselves can become a source of weapons for various groups.
Thirdly, the actions of pirates can at any moment result in a major environmental disaster, as it almost happened with the Takayama tanker.

However, at present, the Indian Ocean has become dangerous for exploration, due to pirates who increasingly began to attack peaceful ships.

Section VI - environmentalists (2 people)

What is researched, the main problem: What environmental problems and why arise in the Indian Ocean.

(slide number 19)

Ecological problems.

1 speaker.

  1. Oil pollution
  2. The social level of the population (sewage is dumped into rivers, poor states, standard of living)
  3. Emissions from / hoz. waste, chemical waste. Harmless, practically unknown organisms, natural phenomena acquire unexpectedly threatening properties. Who worried about algae a dozen years ago? Meanwhile, due to the unreasonable dumping of waste from industrial and agricultural enterprises into the seas and rivers, different types of algae began to develop very quickly there, taking a large amount of oxygen and thereby depriving other inhabitants of the sea of ​​it.

    Oil and oil stains on the surface of the sea water interfere with the life of birds and other animals. Chemical emissions, poisoning marine animals, then send people who feed on them. Is there a way out?

Students share their opinions.

World Oceans Day is a UN commemorative day. Celebrated every year

2 speaker.

Here is the impact of various types of human economic activity on the nature of the Indian Ocean.

Make a cause-and-effect chain.

(Guided by the student with the class.)

"Environmental Training"

  1. Offshore mining
  2. Pollution of ocean and coast waters with harmful substances
  3. Impoverishment of the organic world
  4. Deterioration of air composition and quality
  5. Deteriorating human health

- In any natural community, everything is interconnected, and a person must know these connections so as not to destroy the harmony of the life of nature.

The ocean plays a huge role in shaping the Earth's climate .

IV. Consolidation of the studied material:

Secretary: The conference considered 6 problematic issues, all of them were recorded by me. (The solution to the problem is recorded by the secretary, and the ships put on sails of a certain color as the decisions are made.)

(slide number 20)

In the first section - what is the purpose of research in the Indian Ocean.

Decision-making: Expeditions are carried out in order to study the "living" sections of the earth's crust in order to avoid serious consequences, to warn the population.

For the second section, compare the statistics of the oceans and determine the significance of the Indian Ocean.

Decision-making: Statistics gives us the opportunity to compare, compare.

After analyzing the diagrams, we made decisions that the Indian Ocean is the warmest, most saline and ranks 3rd in area relative to other oceans.

On the third section - why the Indian Ocean is the warmest.

Decision-making: Having studied the climatic conditions of the Indian Ocean, we can safely say that it is rightfully the warmest, since most of it is located in the equatorial and tropical zones.

According to the fourth section - what determined the originality and uniqueness of the animal and plant world.

Decision-making: Since this ocean is the warmest, this determined the uniqueness and diversity of the organic world, the presence of endemics and relics.

On the fifth section - what are the social and economic problems of the local population.

Why is it so attractive to tourists?

Decision-making: After analyzing the situation of social and economic problems, we found out that such a phenomenon as pirates appeared in the Indian Ocean. How to fix this problem? It is necessary to adjust the level of economic development in the countries adjacent to the water area, to provide jobs.

On the sixth section - what environmental problems and why do they arise in Acting.

Decision-making:

– Install treatment facilities at oil production facilities

– Monitor the composition and quality of water and air

- Introduce and control penalties

— Instill environmental education among the local population

Conduct environmental campaigns and events among young people

Guys, we have compiled a collective appeal to the representative of the Greenpeace organization with radical measures to solve environmental, social and economic problems.

And we would like to send the second letter to the representative of the Green Sprout school environmental organization, as an appeal to all schoolchildren. We recommend that you use the developed material at school environmental conferences.

Lesson summary:

Members of the conference check the forms and give grades for the work in the lesson.

Teacher:

You can actually be strong

And the winds can blow you.

But if you don't see the goal

You will never get there. (slide number 21)

So, guys, I will ask you to imagine the emotions that you received in the lesson. If the information that you heard and saw today was interesting, new, fill the sails with wind and send them on trips to other oceans to learn a lot more new things (green).

If the lesson was ordinary, and you didn’t learn anything new for yourself, then raise the blue sails. And if you were just watching our conference from the shore, raise the red sails.

I declare the meeting of sections of the scientific - research conference closed.

VI. Homework:

- Study § 11 - 12 (slide number 22)

The lesson is over, thank you all.

The Indian Ocean is an integral part of the world's oceans. Its maximum depth is 7729 m (Zonda Trench), and the average depth is just over 3700 m, which is the second result after the depths of the Pacific Ocean. The size of the Indian Ocean is 76.174 million km2. This is 20% of the world's oceans. The volume of water is about 290 million km3 (together with all the seas).

The waters of the Indian Ocean are distinguished by their light blue color and good transparency. This is due to the fact that very few freshwater rivers flow into it, which are the main "troublemakers". By the way, due to this, the water in the Indian Ocean is much saltier compared to the salinity of other oceans.

Location of the Indian Ocean

Most of the Indian Ocean is in the Southern Hemisphere. It borders Asia to the north, Antarctica to the south, Australia to the east, and the African continent to the west. In addition, in the southeast, its waters connect with the waters of the Pacific Ocean, and in the southwest with the Atlantic Ocean.

Seas and gulfs of the Indian Ocean

The Indian Ocean does not have as many seas as other oceans. For example, in comparison with the Atlantic Ocean, they are 3 times less. Most of the seas are located in its northern part. In the tropical zone are: Red (the most salty sea on Earth), Laccadive, Arabian, Arafura, Timor and Andaman seas. The Antarctic zone hosts the d'Urville, Commonwealth, Davis, Riiser-Larsen, Cosmonauts seas.

The largest bays of the Indian Ocean are the Persian, Bengal, Oman, Aden, Prydz and the Great Australian.

Indian Ocean islands

The Indian Ocean is not distinguished by an abundance of islands. The largest islands of continental origin are Madagascar, Sumatra, Sri Lanka, Java, Tasmania, Timor. Also, there are volcanic islands, such as Mauritius, Renyon, Kerguelen, and coral - Chagos, Maldives, Andaman, etc.

Underwater world of the Indian Ocean

Since more than half of the Indian Ocean is located in the tropical and subtropical zones, its underwater world is very rich and diverse in terms of species. The coastal zone in the tropics is replete with numerous colonies of crabs and unique fish - mudskippers. Corals live in shallow waters, and various algae grow in temperate waters - calcareous, brown, red.

The Indian Ocean is home to dozens of species of crustaceans, molluscs and jellyfish. A fairly large number of sea snakes also live in the ocean waters, among which there are also poisonous species.

Sharks are a special pride of the Indian Ocean. Its waters are plowed by many species of these predators, namely tiger, mako, gray, blue, great white sharks, etc.

Mammals are represented by killer whales and dolphins. Several species of pinnipeds (seals, dugongs, seals) and whales live in the southern part of the ocean.

Despite all the richness of the underwater world, seafood fishing in the Indian Ocean is rather poorly developed - only 5% of the world's catch. Sardines, tuna, shrimp, lobsters, rays and lobsters are harvested in the ocean.

1. The ancient name of the Indian Ocean is Eastern.

2. In the Indian Ocean, ships are regularly found in good condition, but without a crew. Where he disappears is a mystery. Over the past 100 years, there have been 3 such ships - Tarbon, Houston Market (tankers) and the Cabin Cruiser.

3. Many species of the underwater world of the Indian Ocean have a unique property - they can glow. This is what explains the appearance of luminous circles in the ocean.

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The Indian Ocean is the third largest ocean on Earth, covering about 20% of its water surface. Its area is 76.17 million km², volume - 282.65 million km³. The deepest point of the ocean is in the Sunda Trench (7729 m).

  • Area: 76,170 thousand km²
  • Volume: 282,650 thousand km³
  • Maximum depth: 7729 m
  • Average depth: 3711 m

In the north it washes Asia, in the west - Africa, in the east - Australia; in the south it borders on Antarctica. The border with the Atlantic Ocean runs along the 20 ° meridian of east longitude; from the Pacific - along the 146 ° 55 'meridian of eastern longitude. The northernmost point of the Indian Ocean is located at approximately 30° north latitude in the Persian Gulf. The width of the Indian Ocean is approximately 10,000 km between the southern points of Australia and Africa.

Etymology

The ancient Greeks called the western part of the ocean known to them with adjacent seas and bays the Erythrean Sea (ancient Greek Ἐρυθρά θάλασσα - Red Sea, and in old Russian sources the Red Sea). Gradually, this name began to be attributed only to the nearest sea, and the ocean gets its name from India, the country most famous at that time for its wealth on the shores of the ocean. So Alexander the Great in the IV century BC. e. calls it Indicon Pelagos (ancient Greek Ἰνδικόν πέλαγος) - "Indian Sea". Among the Arabs, it is known as Bar-el-Hind (modern Arabic المحيط الهندي‎‎ - al-mụkhіt al-hindi) - "Indian Ocean". Since the 16th century, the name Oceanus Indicus (lat. Oceanus Indicus) introduced by the Roman scientist Pliny the Elder back in the 1st century was established - the Indian Ocean.

Physical and geographical characteristics

General information

The Indian Ocean is mainly located south of the Tropic of Cancer between Eurasia to the north, Africa to the west, Australia to the east and Antarctica to the south. The border with the Atlantic Ocean runs along the meridian of Cape Agulhas (20 ° E to the coast of Antarctica (Queen Maud Land)). The border with the Pacific Ocean runs: south of Australia - along the eastern border of the Bass Strait to the island of Tasmania, then along the meridian 146 ° 55 'E. to Antarctica; north of Australia - between the Andaman Sea and the Strait of Malacca, further along the southwestern coast of Sumatra, the Sunda Strait, the southern coast of Java, the southern borders of the Bali and Savu seas, the northern border of the Arafura Sea, the southwestern coast of New Guinea and the western border of the Torres Strait . Sometimes the southern part of the ocean, with a northern boundary of 35 ° S. sh. (on the basis of the circulation of water and the atmosphere) up to 60 ° S. sh. (according to the nature of the bottom topography), they are attributed to the Southern Ocean, which is not officially distinguished.

Seas, bays, islands

The area of ​​the seas, bays and straits of the Indian Ocean is 11.68 million km² (15% of the total ocean area), the volume is 26.84 million km³ (9.5%). The seas and main bays located along the coast of the ocean (clockwise): Red Sea, Arabian Sea (Gulf of Aden, Gulf of Oman, Persian Gulf), Laccadive Sea, Bay of Bengal, Andaman Sea, Timor Sea, Arafura Sea (Gulf of Carpentaria), Large Australian Gulf, Mawson Sea, Davis Sea, Commonwealth Sea, Astronaut Sea (the last four are sometimes referred to as the Southern Ocean).

Some islands - for example, Madagascar, Socotra, Maldives - are fragments of ancient continents, others - Andaman, Nicobar or Christmas Island - are of volcanic origin. The largest island in the Indian Ocean is Madagascar (590 thousand km²). Largest islands and archipelagos: Tasmania, Sri Lanka, Kerguelen Archipelago, Andaman Islands, Melville, Mascarene Islands (Reunion, Mauritius), Kangaroo, Nias, Mentawai Islands (Siberut), Socotra, Groot Island, Comoros, Tiwi Islands (Bathurst ), Zanzibar, Simeulue, Furno (Flinders) Islands, Nicobar Islands, Qeshm, King, Bahrain Islands, Seychelles, Maldives, Chagos Archipelago.

The history of the formation of the Indian Ocean

During the early Jurassic, the ancient supercontinent Gondwana began to break apart. As a result, Africa with Arabia, Hindustan and Antarctica with Australia were formed. The process ended at the turn of the Jurassic and Cretaceous periods (140-130 million years ago), and a young basin of the modern Indian Ocean began to form. In the Cretaceous period, the ocean floor grew due to the movement of Hindustan to the north and the reduction in the area of ​​the Pacific and Tethys oceans. In the Late Cretaceous, the split of the single Australo-Antarctic continent began. At the same time, as a result of the formation of a new rift zone, the Arabian plate broke away from the African plate, and the Red Sea and the Gulf of Aden were formed. At the beginning of the Cenozoic era, the growth of the Indian Ocean stopped towards the Pacific, but continued towards the Tethys Sea. At the end of the Eocene - the beginning of the Oligocene, Hindustan collided with the Asian continent.

Today, the movement of tectonic plates continues. The axis of this movement is the mid-ocean rift zones of the African-Antarctic Ridge, the Central Indian Ridge, and the Australo-Antarctic Rise. The Australian plate continues to move north at a rate of 5-7 cm per year. The Indian plate continues to move in the same direction at a speed of 3-6 cm per year. The Arabian Plate is moving northeast at a rate of 1-3 cm per year. The Somali Plate continues to break away from the African Plate along the East African Rift Zone, which moves at a speed of 1-2 cm per year in a northeasterly direction. On December 26, 2004, in the Indian Ocean near the island of Simeulue, located off the northwestern coast of the island of Sumatra (Indonesia), the largest earthquake with a magnitude of up to 9.3 occurred in the entire history of observations. The reason was a shift of about 1200 km (according to some estimates - 1600 km) of the earth's crust at a distance of 15 m along the subduction zone, as a result of which the Hindustan plate moved under the Burma plate. The earthquake caused a tsunami, which brought enormous destruction and a huge number of deaths (up to 300 thousand people).

Geological structure and topography of the bottom of the Indian Ocean

mid-ocean ridges

Mid-ocean ridges divide the bottom of the Indian Ocean into three sectors: African, Indo-Australian and Antarctic. There are four mid-ocean ridges: the West Indian, Arabian-Indian, Central Indian ridges and the Australo-Antarctic Rise. The West Indian Ridge is located in the southwestern part of the ocean. It is characterized by underwater volcanism, seismicity, rift-type crust and rift structure of the axial zone; it is crossed by several oceanic faults of submeridional strike. In the region of the island of Rodrigues (Mascarene archipelago) there is a so-called triple connection, where the system of ridges is divided to the north into the Arabian-Indian ridge and to the south-west into the Central Indian ridge. The Arabian-Indian ridge is composed of ultramafic rocks, a number of submeridial-trending secant faults have been identified, with which very deep depressions (oceanic troughs) with depths of up to 6.4 km are associated. The northern part of the ridge is crossed by the most powerful Owen Fault, along which the northern segment of the ridge experienced a displacement of 250 km to the north. Further west, the rift zone continues into the Gulf of Aden and north-northwest into the Red Sea. Here the rift zone is composed of carbonate deposits with volcanic ash. In the rift zone of the Red Sea, strata of evaporites and metal-bearing silts associated with powerful hot (up to 70 °C) and very saline (up to 350 ‰) juvenile waters have been found.

In the southwest direction from the triple junction extends the Central Indian Ridge, which has a well-defined rift and flank zones, ending in the south with the Amsterdam volcanic plateau with the volcanic islands of Saint-Paul and Amsterdam. From this plateau, the Australo-Antarctic Rise extends to the east-southeast, having the form of a wide, slightly dissected arch. In the eastern part, the uplift is dissected by a series of meridional faults into a number of segments displaced relative to each other in the meridional direction.

African segment of the ocean

The underwater margin of Africa has a narrow shelf and a distinct continental slope with marginal plateaus and continental foot. In the south, the African continent forms protrusions pushed to the south: the Agulhas bank, the Mozambique and Madagascar ridges, composed of continental-type earth's crust. The mainland foot forms a sloping plain extending south along the coast of Somalia and Kenya, which continues in the Mozambique Channel and borders Madagascar from the east. The Mascarene Range runs along the east of the sector, in the northern part of which the Seychelles are located.

The surface of the ocean floor in the sector, especially along the mid-ocean ridges, is dissected by numerous ridges and troughs associated with submeridional fault zones. There are many underwater volcanic mountains, most of which are built on coral superstructures in the form of atolls and underwater coral reefs. Between the mountain rises there are basins of the ocean floor with a hilly and mountainous relief: Agulhas, Mozambique, Madagascar, Mascarene and Somali. In the Somali and Mascarene basins, vast flat abyssal plains are formed, where a significant amount of terrigenous and biogenic sedimentary material enters. In the Mozambique Basin, there is an underwater valley of the Zambezi River with a system of alluvial fans.

Indo-Australian segment of the ocean

The Indo-Australian segment occupies half the area of ​​the Indian Ocean. In the west, in the meridional direction, the Maldives Range passes, on the top surface of which the islands of Laccadive, Maldives and Chagos are located. The ridge is composed of continental-type crust. A very narrow shelf, a narrow and steep continental slope, and a very wide continental foot stretched along the coast of Arabia and Hindustan, mainly formed by two giant fans of turbid streams of the Indus and Ganges rivers. These two rivers carry 400 million tons of debris into the ocean. The Indus cone extends far into the Arabian Basin. And only the southern part of this basin is occupied by a flat asbyssal plain with separate seamounts.

Almost exactly 90° E. The blocky oceanic East Indian Ridge stretches for 4,000 km from north to south. Between the Maldives and the East Indian Ranges is the Central Basin - the largest basin of the Indian Ocean. Its northern part is occupied by the Bengal alluvial fan (from the Ganges River), to the southern border of which the abyssal plain adjoins. In the central part of the basin there is a small Lanka ridge and the Afanasy Nikitin seamount. To the east of the East Indian Ridge are the Cocos and Western Australian Basins, separated by a blocky sublatitudinally oriented Cocos Rise with the Cocos and Christmas Islands. In the northern part of the Coconut Basin there is a flat abyssal plain. From the south, it is bounded by the West Australian Rise, which drops steeply to the south and gently plunges under the bottom of the basin to the north. From the south, the West Australian Rise is bounded by a steep ledge associated with the Diamantina Fault Zone. The ralome zone combines deep and narrow grabens (the most significant are the Ob and Diamatina) and numerous narrow horsts.

The transitional region of the Indian Ocean is represented by the Andaman Trench and the deep-water Sunda Trench, which is associated with the maximum depth of the Indian Ocean (7209 m). The outer ridge of the Sunda island arc is the underwater Mentawai Range and its continuation in the form of the Andaman and Nicobar Islands.

Underwater margin of the Australian mainland

The northern part of the Australian continent is bordered by a wide Sahul shelf with many coral structures. To the south, this shelf narrows and widens again off the coast of southern Australia. The continental slope is composed of marginal plateaus (the largest of them are the Exmouth and Naturalists plateaus). In the western part of the Western Australian Basin, the Zenith, Cuvier and other rises are located, which are pieces of the continental structure. Between the southern underwater margin of Australia and the Australo-Antarctic Rise, there is a small South Australian Basin, which is a flat abyssal plain.

Antarctic segment of the ocean

The Antarctic segment is bounded by the West Indian and Central Indian ridges, and from the south by the coast of Antarctica. Under the influence of tectonic and glaciological factors, the shelf of Antarctica is overdeepened. A wide continental slope is cut by large and wide canyons, through which supercooled water flows from the shelf into the abyssal depressions. The continental foot of Antarctica is distinguished by a wide and significant (up to 1.5 km) thickness of loose deposits.

The largest protrusion of the Antarctic continent is the Kerguelen Plateau, as well as the volcanic uplift of the Prince Edward and Crozet Islands, which divide the Antarctic sector into three basins. To the west is the African-Antarctic Basin, which is half located in the Atlantic Ocean. Most of its bottom is a flat abyssal plain. The Crozet Basin, located to the north, is characterized by a large-hilly bottom topography. The Australo-Antarctic Basin, lying to the east of Kerguelen, is occupied in the southern part by a flat plain, and in the northern part by Abyssotian hills.

Bottom sediments

The Indian Ocean is dominated by calcareous foraminiferal-coccolithic deposits, which occupy more than half of the bottom area. The wide development of biogenic (including coral) calcareous deposits is explained by the position of a large part of the Indian Ocean within the tropical and equatorial belts, as well as by the relatively shallow depth of oceanic basins. Numerous mountain uplifts are also favorable for the formation of lime deposits. In the deep parts of some basins (for example, the Central, Western Australian), deep-sea red clays occur. The equatorial belt is characterized by radiolarian muds. In the southern cold part of the ocean, where the conditions for the development of diatom flora are especially favorable, siliceous diatom deposits are represented. Iceberg sediments are deposited off the Antarctic coast. At the bottom of the Indian Ocean, ferromanganese nodules are widely distributed, confined mainly to areas of deposition of red clays and radiolarian oozes.

Climate

In this region, four climatic zones are distinguished, stretched along the parallels. Under the influence of the Asian continent, a monsoonal climate is established in the northern part of the Indian Ocean with frequent cyclones moving towards the coasts. High atmospheric pressure over Asia in winter causes the northeast monsoon to form. In summer, it is replaced by a humid southwest monsoon, carrying air from the southern regions of the ocean. During the summer monsoon, there is often a wind force of more than 7 points (with a frequency of 40%). In summer, the temperature over the ocean is 28-32 °C, in winter it drops to 18-22 °C.

In the southern tropics, the southeast trade wind dominates, which in winter does not extend north of 10°N. The average annual temperature reaches 25 °C. In the zone 40-45°S. Throughout the year, the western transfer of air masses is characteristic, it is especially strong in temperate latitudes, where the frequency of storm weather is 30-40%. In the mid-ocean, stormy weather is associated with tropical hurricanes. In winter, they can also occur in the southern tropical zone. Most often, hurricanes occur in the western part of the ocean (up to 8 times a year), in the areas of Madagascar and the Mascarene Islands. In subtropical and temperate latitudes, the temperature reaches 10-22 °C in summer and 6-17 °C in winter. Strong winds are characteristic from 45 degrees and south. In winter, the temperature here ranges from -16 °C to 6 °C, and in summer - from -4 °C to 10 °C.

The maximum amount of precipitation (2.5 thousand mm) is confined to the eastern region of the equatorial zone. There is also increased cloudiness (more than 5 points). The least amount of precipitation is observed in the tropical regions of the southern hemisphere, especially in the eastern part. In the northern hemisphere, clear weather is characteristic of the Arabian Sea for most of the year. The maximum cloudiness is observed in Antarctic waters.

Hydrological regime of the Indian Ocean

Surface water circulation

In the northern part of the ocean, there is a seasonal change in currents caused by monsoon circulation. In winter, the Southwest Monsoon Current sets in, starting in the Bay of Bengal. South of 10° N. sh. this current passes into the Western Current, crossing the ocean from the Nicobar Islands to the coast of East Africa. Further, it branches: one branch goes north to the Red Sea, the other - south to 10 ° S. sh. and, turning to the east, gives rise to the Equatorial countercurrent. The latter crosses the ocean and, off the coast of Sumatra, again divides into a part that goes into the Andaman Sea and the main branch, which between the Lesser Sunda Islands and Australia goes to the Pacific Ocean. In summer, the southeast monsoon ensures the movement of the entire mass of surface water to the east, and the Equatorial countercurrent disappears. The summer monsoon current begins off the coast of Africa with the powerful Somali current, which is joined by the current from the Red Sea in the Gulf of Aden. In the Bay of Bengal, the summer monsoon current divides into north and south, which flows into the South Equatorial Current.

In the southern hemisphere, currents are constant, without seasonal fluctuations. Driven by the trade winds, the South Trade Wind Current crosses the ocean from east to west towards Madagascar. It intensifies in winter (for the southern hemisphere) due to additional feeding by the waters of the Pacific Ocean coming along the northern coast of Australia. At Madagascar, the South Equatorial Current forks, giving rise to the Equatorial Countercurrent, Mozambique and Madagascar currents. Merging southwest of Madagascar, they form the warm Agulhas current. The southern part of this current goes into the Atlantic Ocean, and part of it flows into the westerly winds. On the approach to Australia, the cold West Australian Current departs from the latter to the north. Local gyres operate in the Arabian Sea, the Bengal and Great Australian Bays, and in Antarctic waters.

The northern part of the Indian Ocean is characterized by the predominance of a semidiurnal tide. The amplitudes of the tide in the open ocean are small and average 1 m. In the Antarctic and subantarctic zones, the amplitude of the tides decreases from east to west from 1.6 m to 0.5 m, and near the coast they increase to 2-4 m. The maximum amplitudes are noted between islands, in shallow bays. In the Bay of Bengal, the tide is 4.2-5.2 m, near Mumbai - 5.7 m, near Yangon - 7 m, near northwestern Australia - 6 m, and in the port of Darwin - 8 m. In other areas, the amplitude of the tides about 1-3 m.

temperature, salinity

In the equatorial zone of the Indian Ocean, the surface water temperature is about 28 ° C all year round in both the western and eastern parts of the ocean. In the Red and Arabian Seas, winter temperatures drop to 20-25 °C, but in summer the maximum temperatures for the entire Indian Ocean are set in the Red Sea - up to 30-31 °C. High winter water temperatures (up to 29 ° C) are typical for the coasts of northwestern Australia. In the southern hemisphere, at the same latitudes in the eastern part of the ocean, the water temperature in winter and summer is 1-2° lower than in the western part. Water temperatures below 0°C in summer are found south of 60°S. sh. Ice formation in these areas begins in April and the thickness of the fast ice reaches 1-1.5 m by the end of winter. Melting begins in December-January, and by March the waters are completely cleared of fast ice. In the southern part of the Indian Ocean, icebergs are common, sometimes setting north of 40 ° S. sh.

The maximum salinity of surface waters is observed in the Persian Gulf and the Red Sea, where it reaches 40-41 ‰. High salinity (more than 36 ‰) is also observed in the southern tropical zone, especially in the eastern regions, and in the northern hemisphere also in the Arabian Sea. In the neighboring Bay of Bengal, due to the desalination effect of the Ganges runoff from the Brahmaputra and the Irrawaddy, the salinity is reduced to 30-34 ‰. Increased salinity correlates with areas of maximum evaporation and the least amount of precipitation. Reduced salinity (less than 34 ‰) is characteristic of subarctic waters, where the strong freshening effect of melted glacial waters is felt. The seasonal difference in salinity is significant only in the Antarctic and equatorial zones. In winter, desalinated waters from the northeastern part of the ocean are carried by the monsoon current, forming a tongue of low salinity along 5°N. sh. In summer, this language disappears. In the Arctic waters in winter, salinity slightly increases due to the salinization of waters in the process of ice formation. Salinity decreases from the surface to the bottom of the ocean. Bottom waters from the equator to the arctic latitudes have a salinity of 34.7-34.8 ‰.

water masses

The waters of the Indian Ocean are divided into several water masses. In the part of the ocean north of 40 ° S. sh. they distinguish central and equatorial surface and subsurface water masses and underlying them (deeper than 1000 m) deep. To the north to 15-20 ° S. sh. the central water mass spreads. The temperature varies with depth from 20-25 °C to 7-8 °C, salinity is 34.6-35.5 ‰. Surface layers north of 10-15°S sh. make up the equatorial water mass with a temperature of 4-18 ° C and a salinity of 34.9-35.3 ‰. This water mass is characterized by significant speeds of horizontal and vertical movement. In the southern part of the ocean, there are subantarctic (temperature 5-15 ° C, salinity up to 34 ‰) and Antarctic (temperature from 0 to -1 ° C, salinity drops to 32 ‰ due to melting ice). Deep water masses are divided into: very cold circulation, formed by lowering the Arctic water masses and the inflow of circulation water from the Atlantic Ocean; South Indian, formed as a result of lowering subarctic surface waters; North Indian, formed by dense waters flowing from the Red Sea and the Gulf of Oman. Deeper than 3.5-4 thousand m, bottom water masses are common, formed from the Antarctic supercooled and dense salt waters of the Red Sea and the Persian Gulf.

Flora and fauna

The flora and fauna of the Indian Ocean is extremely diverse. The tropical region stands out for its abundance of plankton. The single-celled alga Trichodesmium (cyanobacteria) is especially abundant, due to which the surface layer of water becomes very cloudy and changes its color. The plankton of the Indian Ocean is distinguished by a large number of night-luminous organisms: peridine, some species of jellyfish, ctenophores, and tunicates. Brightly colored siphonophores, including poisonous physalia, are abundant. In temperate and arctic waters, the main representatives of plankton are copepods, euphausids and diatoms. The most numerous fish of the Indian Ocean are dolphins, tuna, notothenia and various sharks. From reptiles there are several species of giant sea turtles, sea snakes, from mammals - cetaceans (toothless and blue whales, sperm whales, dolphins), seals, sea elephants. Most cetaceans live in temperate and polar regions, where, due to the intensive mixing of waters, favorable conditions arise for the development of planktonic organisms. Birds are represented by albatrosses and frigatebirds, as well as several species of penguins that inhabit the coasts of South Africa, Antarctica and islands in the temperate ocean.

The flora of the Indian Ocean is represented by brown algae (Sargasso, Turbinarium) and green algae (Caulerpa). The calcareous algae lithotamnia and chalimeda also flourish and participate together with corals in the construction of reef structures. In the process of activity of reef-forming organisms, coral platforms are created, sometimes reaching a width of several kilometers. Typical for the coastal zone of the Indian Ocean is a phytocenosis formed by mangroves. Such thickets are especially characteristic of river mouths and occupy large areas in Southeast Africa, western Madagascar, Southeast Asia and other areas. For temperate and Antarctic waters, the most characteristic are red and brown algae, mainly from the groups of fucus and kelp, porphyry, and helidium. In the subpolar regions of the southern hemisphere, giant macrocystis are found.

Zoobenthos is represented by a variety of mollusks, calcareous and flint sponges, echinoderms (sea urchins, starfish, brittle stars, holothurians), numerous crustaceans, hydroids, and bryozoans. Coral polyps are widespread in the tropical zone.

Ecological problems

Human economic activity in the Indian Ocean has led to the pollution of its waters and to the reduction of biodiversity. At the beginning of the 20th century, some species of whales were almost completely exterminated, others - sperm whales and sei whales - still survived, but their number was greatly reduced. Since the 1985-1986 season, the International Whaling Commission has introduced a complete moratorium on commercial whaling of any kind. In June 2010, at the 62nd meeting of the International Whaling Commission, under pressure from Japan, Iceland and Denmark, the moratorium was suspended. The Mauritius dodo, destroyed by 1651 on the island of Mauritius, became a symbol of extinction and extinction of species. After it became extinct, people first formed the opinion that they could cause the extinction of other animals.

A great danger in the ocean is the pollution of waters with oil and oil products (the main pollutants), some heavy metals, and waste from the nuclear industry. The routes of oil tankers transporting oil from the countries of the Persian Gulf run across the ocean. Any major accident can lead to an ecological disaster and the death of many animals, birds and plants.

States of the Indian Ocean

States along the borders of the Indian Ocean (clockwise):

  • Republic Of South Africa,
  • Mozambique,
  • Tanzania,
  • Kenya,
  • Somalia,
  • Djibouti,
  • Eritrea,
  • Sudan,
  • Egypt,
  • Israel,
  • Jordan,
  • Saudi Arabia,
  • Yemen,
  • Oman,
  • United Arab Emirates,
  • Qatar,
  • Kuwait,
  • Iraq,
  • Iran,
  • Pakistan,
  • India,
  • Bangladesh,
  • Myanmar,
  • Thailand,
  • Malaysia,
  • Indonesia,
  • East Timor,
  • Australia.

In the Indian Ocean there are island states and possessions of states outside the region:

  • Bahrain,
  • British Indian Ocean Territory (UK),
  • Comoros,
  • Mauritius,
  • Madagascar,
  • Mayotte (France),
  • Maldives,
  • Reunion (France),
  • Seychelles,
  • French Southern and Antarctic Territories (France),
  • Sri Lanka.

Research History

The shores of the Indian Ocean are one of the areas of settlement of the most ancient peoples and the emergence of the first river civilizations. In ancient times, ships such as junks and catamarans were used by people for sailing, with favorable monsoons from India to East Africa and back. The Egyptians in 3500 BC conducted a brisk maritime trade with the countries of the Arabian Peninsula, India and East Africa. The countries of Mesopotamia for 3000 years BC made sea trips to Arabia and India. From the 6th century BC, the Phoenicians, according to the Greek historian Herodotus, made sea voyages from the Red Sea across the Indian Ocean to India and around Africa. In the 6th-5th centuries BC, Persian merchants conducted maritime trade from the mouth of the Indus River along the east coast of Africa. At the end of the Indian campaign of Alexander the Great in 325 BC, the Greeks with a huge fleet with a crew of five thousand in severe storm conditions made a many-month voyage between the mouths of the Indus and Euphrates rivers. Byzantine merchants in the 4th-6th centuries penetrated in the east to India, and in the south - to Ethiopia and Arabia. Starting from the 7th century, Arab sailors began intensive exploration of the Indian Ocean. They perfectly studied the coast of East Africa, West and East India, the islands of Socotra, Java and Ceylon, visited the Laccadives and Maldives, the islands of Sulawesi, Timor and others.

At the end of the 13th century, the Venetian traveler Marco Polo, on his way back from China, passed through the Indian Ocean from Malacca to the Strait of Hormuz, visiting Sumatra, India, and Ceylon. The journey was described in the Book of the Diversity of the World, which had a significant impact on navigators, cartographers, and writers of the Middle Ages in Europe. Chinese junks made trips along the Asian shores of the Indian Ocean and reached the Eastern coast of Africa (for example, Zheng He's seven voyages in 1405-1433). The expedition, led by the Portuguese navigator Vasco da Gama, rounded Africa from the south, passing along the eastern coast of the continent in 1498, reached India. In 1642, the Dutch trading East India Company organized an expedition of two ships under the command of Captain Tasman. As a result of this expedition, the central part of the Indian Ocean was explored and it was proved that Australia is the mainland. In 1772, a British expedition under the command of James Cook penetrated the southern Indian Ocean to 71°S. sh., while extensive scientific material on hydrometeorology and oceanography was obtained.

From 1872 to 1876, the first scientific oceanic expedition took place on the English sailing-steam corvette Challenger, new data were obtained on the composition of the ocean waters, on the flora and fauna, on the bottom topography and soils, the first map of the depths of the ocean was compiled and the first collection was collected. deep sea animals. The round-the-world expedition on the Russian propeller-sailing corvette "Vityaz" of 1886-1889 under the leadership of the scientist-oceanographer S. O. Makarov conducted a large-scale research work in the Indian Ocean. A great contribution to the study of the Indian Ocean was made by oceanographic expeditions on the German ships Valkyrie (1898-1899) and Gauss (1901-1903), on the English ship Discovery II (1930-1951), the Soviet expeditionary ship Ob ( 1956-1958) and others. In 1960-1965, under the auspices of the Intergovernmental Oceanographic Expedition under UNESCO, an international Indian Ocean Expedition was carried out. She was the largest of all the expeditions ever to work in the Indian Ocean. The program of oceanographic work covered almost the entire ocean with observations, which was facilitated by the participation of scientists from about 20 countries in the research. Among them: Soviet and foreign scientists on the research ships Vityaz, A. I. Voeikov”, “Yu. M. Shokalsky, non-magnetic schooner Zarya (USSR), Natal (South Africa), Diamantina (Australia), Kistna and Varuna (India), Zulfikvar (Pakistan). As a result, valuable new data were collected on hydrology, hydrochemistry, meteorology, geology, geophysics and biology of the Indian Ocean. Since 1972, the American ship Glomar Challenger has carried out regular deep-sea drilling, work on the study of the movement of water masses at great depths, and biological research.

In recent decades, numerous measurements of the ocean have been carried out using space satellites. The result was a bathymetric atlas of the oceans released in 1994 by the US National Geophysical Data Center with a map resolution of 3-4 km and a depth accuracy of ±100 m.

Economic importance

Fishing and marine industries

The importance of the Indian Ocean for the world fishing industry is small: the catches here are only 5% of the total. The main commercial fish of the local waters are tuna, sardine, anchovy, several species of sharks, barracudas and rays; Shrimps, lobsters and lobsters are also caught here. Until recently, whaling, which was intensive in the southern regions of the ocean, is rapidly curtailing due to the almost complete extermination of some species of whales. On the northwestern coast of Australia, in Sri Lanka and the Bahrain Islands, pearls and mother-of-pearl are mined.

Transport routes

The most important transport routes of the Indian Ocean are routes from the Persian Gulf to Europe, North America, Japan and China, as well as from the Gulf of Aden to India, Indonesia, Australia, Japan and China. The main navigable straits of the Indian Strait: Mozambique, Bab-el-Mandeb, Hormuz, Sunda. The Indian Ocean is connected by the artificial Suez Canal to the Mediterranean Sea of ​​the Atlantic Ocean. In the Suez Canal and the Red Sea, all the main cargo flows of the Indian Ocean converge and diverge. Major ports: Durban, Maputo (export: ore, coal, cotton, minerals, oil, asbestos, tea, raw sugar, cashew nuts, import: machinery and equipment, manufactured goods, food), Dar es Salaam (export : cotton, coffee, sisal, diamonds, gold, oil products, cashew nuts, cloves, tea, meat, leather, import: manufactured goods, food, chemicals), Jeddah, Salalah, Dubai, Bandar Abbas, Basra (export: oil, grain, salt, dates, cotton, leather, import: cars, timber, textiles, sugar, tea), Karachi (export: cotton, fabrics, wool, leather, shoes, carpets, rice, fish, import: coal, coke, oil products , mineral fertilizers, equipment, metals, grain, food, paper, jute, tea, sugar), Mumbai (export: manganese and iron ores, oil products, sugar, wool, leather, cotton, fabrics, import: oil, coal, cast iron, equipment, grain, chemicals, manufactured goods), Colombo, Chennai (iron ore, coal, granite, fertilizers, petroleum products, containers, vehicles), Kolkata (export: coal, iron and copper ores, tea, imports: manufactured goods, grain, foodstuffs, equipment), Chittagong (clothing, jute, leather, tea, chemicals), Yangon (exports: rice, hardwood, non-ferrous metals, bagasse, legumes, rubber, precious stones, import: coal, cars, foodstuffs, fabrics), Perth Fremantle (export: ores, alumina, coal, coke, caustic soda, phosphate raw materials, import: oil, equipment).

Minerals

The most important minerals of the Indian Ocean are oil and natural gas. Their deposits are found on the shelves of the Persian and Suez Gulfs, in the Bass Strait, on the shelf of the Hindustan Peninsula. On the coasts of India, Mozambique, Tanzania, South Africa, the islands of Madagascar and Sri Lanka, ilmenite, monazite, rutile, titanite and zirconium are exploited. Off the coast of India and Australia there are deposits of barite and phosphorite, and in the shelf zones of Indonesia, Thailand and Malaysia, deposits of cassiterite and ilmenite are exploited on an industrial scale.

Recreational resources

The main recreational areas of the Indian Ocean: the Red Sea, the western coast of Thailand, the islands of Malaysia and Indonesia, the island of Sri Lanka, the area of ​​coastal urban agglomerations of India, the eastern coast of Madagascar, the Seychelles and Maldives. Among the countries of the Indian Ocean with the largest flow of tourists (according to 2010 data from the World Tourism Organization) stand out: Malaysia (25 million visits per year), Thailand (16 million), Egypt (14 million), Saudi Arabia (11 million), South Africa (8 million), United Arab Emirates (7 million), Indonesia (7 million), Australia (6 million), India (6 million), Qatar (1.6 million), Oman (1.5 million).

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The Indian Ocean is the third largest ocean on Earth, covering about 20% of its water surface. Its area is 90.17 million km2; volume - 210 million km3. The boundary between the Indian and Atlantic Oceans runs along the meridian 20° East, and between the Indian and Pacific Oceans runs along the meridian 147° East. The northernmost point of the Indian Ocean is located at approximately 30° north latitude in the Persian Gulf. The width of the Indian Ocean is approximately 10,000 km between the southern points of Australia and Africa. The nature of the Indian Ocean has many similarities with the nature of the Pacific Ocean, especially in the organic world of the two oceans. The Indian Ocean has a peculiar position on the planet: most of it lies in the South hemisphere. In the north, it is limited by Eurasia and has no connection with the Arctic Ocean. The ocean shores are slightly indented. There are relatively few islands. Large islands are located only on the border of the ocean. There are volcanic and coral islands in the ocean.
The Indian Ocean is located entirely in the Eastern Hemisphere between Africa - in the west, Eurasia - in the north, the Sunda Islands and Australia - in the east, Antarctica - in the south. The Indian Ocean in the southwest communicates widely with the Atlantic Ocean, and in the southeast with the Pacific. The coastline is poorly dissected. There are eight seas in the ocean, there are large bays.
The main part of the Indian Ocean lies in the equatorial, subequatorial and tropical zones, only the southern part covers high latitudes, up to the subantarctic. The main feature of the ocean's climate is the seasonal monsoon winds in its northern part, which is significantly influenced by land. Therefore, in the northern part of the ocean there are two seasons of the year - a warm, quiet, sunny winter and a hot, cloudy, rainy, stormy summer. South of 10°S dominated by the southeast trade wind. To the south, in temperate latitudes, a strong and steady westerly wind blows. The amount of precipitation is significant in the equatorial zone - up to 3000 mm per year. There is very little precipitation off the coast of Arabia, in the Red Sea and the Persian Gulf.
In the northern part of the ocean, the formation of currents is influenced by the change of monsoons, which rebuilds the system of currents according to the seasons of the year: summer monsoon - in the direction from west to east, winter - from east to west. In the southern part of the ocean, the most significant are the South Equatorial Current and the Western Wind Current. The south of the Indian Ocean is experiencing a significant cooling effect of Antarctica; here are the most severe regions of the ocean
The average surface water temperature is +17°C. The slightly lower average temperature is explained by the strong cooling effect of the Antarctic waters. The northern part of the ocean warms up well, is deprived of the influx of cold waters and is therefore the warmest. In summer, the water temperature in the Persian Gulf rises to +34°C. In the southern hemisphere, the temperature of the waters gradually decreases with increasing latitude. The salinity of surface waters in many areas is higher than average, and in the Red Sea it is especially high (up to 42 ppm).
It has a lot in common with the Pacific Ocean. The species composition of fish is rich and varied. Sardinella, anchovy, mackerel, tuna, dolphin, sharks, flying fish live in the northern part of the Indian Ocean. In southern waters - notothenia and white-blooded fish; there are cetaceans and pinnipeds. The organic world of the shelf and coral reefs is especially rich. Thickets of algae border the coast of Australia, South Africa, islands. There are large commercial accumulations of crustaceans (lobsters, shrimps, krill, etc.). In general, the biological resources of the Indian Ocean are still poorly studied and underutilized.
The northern part of the ocean lies in the tropical zone. Under the influence of the surrounding land and monsoon circulation, several aquatic complexes are formed in this belt, differing in the properties of water masses. Especially sharp differences are noted in the salinity of the waters.
In the equatorial zone, the temperature of surface waters almost does not change during the seasons. Above the numerous uplifts of the bottom and near the coral islands in this belt, a lot of plankton develops, and bioproductivity increases. The biological resources of the Indian Ocean have been used by the inhabitants of the coasts since time immemorial. And until now, handicrafts of fish and other seafood retain an important role in the economy of many countries. However, the natural resources of the ocean are used to a lesser extent than in other oceans. The biological productivity of the ocean as a whole is low; it increases only on the shelf and the continental slope.
A comprehensive study of the ocean began at the end of the 19th century. The most significant research was carried out by the British expedition on board the Challenger. However, until the middle of the twentieth century. The Indian Ocean has been poorly studied.

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